In general, a lens has various aberrations, such as chromatic aberration, distortion, peripheral light falloff, and blurring, attributed to the characteristics of the lens, which leads to degradation in the image quality. Moreover, it is known that various aberrations change according to the focal length, the aperture, and the focus position (hereinafter referred to as “the optical parameters”) as well as the distance from the optical axis center of the lens.
Therefore, a conventional image pickup apparatus includes a memory in which the characteristics of the lens are stored in advance for each optical parameter. The image pickup apparatus reads out the lens characteristics from the memory according to set optical parameters and executes optical correction processes of various aberrations based on the lens characteristics. If the lens characteristics corresponding to the set optical parameters are not stored in the memory, the lens characteristics are generated as the neighborhood lens characteristics by using the interpolation method (For example, see PTL1).